Well, I finally installed my fuel pressure gauge.
At idle, I am getting 58-60 psi. Driving around & partially agressive driving, the same.
WOT above 5,000 to 6,400 it drops to 52psi.
I have the walbro 255 intank. Are my readings normal?
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Well, I finally installed my fuel pressure gauge.
At idle, I am getting 58-60 psi. Driving around & partially agressive driving, the same.
WOT above 5,000 to 6,400 it drops to 52psi.
I have the walbro 255 intank. Are my readings normal?
If I remember correctly the fuel pressure on the Chiltons book said 52-62 PSI. Sounds like its running out of fuel if its losing pressure, though. You have a one line fuel rail, returnless, correct?
Correct.Quote:
Originally Posted by RedHeartbeat
One thing to check is the charge voltage at those RPMs. As the voltage drops your gauge will read lower and the fuel pump will be less efficient.
Are you talking about adding a voltage booster, like a Magnavolt or something?Quote:
Originally Posted by RedHeartbeat
I have one if you want to try it. I think it is just a bandaid. How much fuel in the tank. I think he might mean check the voltage at the connector by the tank and see what voltage it is at WOT. I have the same fuel pump as you and get no pressure drop at WOT.Quote:
Originally Posted by SCIV
Tank is 1/2 full.Quote:
Originally Posted by GMCwantsLS1
You mean a voltage booster is a patch solution? How in the heck do I check the fuel pump voltage at WOT? You mean run wires back there & into the cab?
Yes you have to run wires into the cab. Or you can hang your son under there, oops bad idea. :doofus:Quote:
Originally Posted by SCIV
But I am still within the spec'd range, so that shouldn't be a big deal. Right?
Makes me think that at 10psi + I ran out of fuel. Then my engine ran outta pistons.
It could just need the ground tightened or the plug cleaned at the tank. It might be fine and just richen the tune to compensate.
The PCM may be commanding the alternator to quit charging during performance mode and that kills voltage to the fuel pump. The voltage booster can help for sure. My radio has a display mode for voltage on it that is digital. I can turn it on and watch the voltage during high RPM runs. A digital multimeter setup in the cab of the truck can show the same thing, watch for dropping voltage during WOT runs.
I have never heard of that before!Quote:
Originally Posted by RedHeartbeat
I guess it will try to see if my Interceptor gauge tells me anything (because I am lazy and don't want to crawl under the truck).
I don't blame you, thats what lifts are for. Theres a rule at the shop no crawling or laying down under vehicles. We sit in chairs under cars/trucks and work! :LOL: Thats lazy. Something else to check 2morrow SC?Quote:
Originally Posted by SCIV
I'm not sure if the PCM is setup to shut down the charging of the alternator or not during WOT runs. Its a load on the engine and only occurs intermittently so I would think that GM would do that to boost WOT power, just as they disable the A/C during WOT runs. That's why the PCM now controls the A/C and field wires in the alternator probably.
Update, the voltage shows 13.7-13.8 under WOT all the way up to shift @ 6,400 rpm.
Sounds great!
Good deal, in one sense. You're just running out of fuel now. Not sure if its the pump or a restiction in a line somewhere. Changed the fuel filter lately?
When I put the pump on. Who's bright idea was it to put the filter in the tank anyway?Quote:
Originally Posted by RedHeartbeat
Edit: I just checked my records and I changed it in January 2006. Probably 20,000 miles ago, and 15,000 of that with the blower. Should it be changed again? If so, who wants to do it?
Look in your owners manual and see what your filter change interval is supposed to be. I think the voltage booster might be your next option if changing the filter doesn't fix it.
I have a Kenny Bell boost a pump if you are interested. I'll let it go cheap if you want to PM me a offer. Here is the thread when I bought it. I have never installed it. F/S Kenne Bell Boost-a-Pump - Page 2 - PerformanceTrucks.net Forums